Roy...OK I also do not want to get into a long drawn out argument....
I answer your questions simply with another question......Do you think that musical knowledge and the ability to understand the structure of chords and melody helps or hinders a lyricist? If the answer is helps then what is the prob in learning....now I am not expecting concert pianist or classical guitarists but some grounding would help a lot.....that is what I mean by a no brainer. The more musical knowledge and ability you have the better lyricist you will be.

To your second question......I do a lot of demo work.....ALWAYS try to do the best job I can...whilst I listen to the lyricist and try to do as he asks...I will often put my own stamp on the piece and sometimes recommend changing a melody or altering some lyrics. I will always ask first and keep people informed of progress. You have to remember that the person producing the demo has a reputation to keep...so there is no point in producing crap. It sometimes is a balancing act but I will try to give a client what he wants but honesty is the best policy......I am sure you will agree that sometimes a fresh pair of ears and mind can take a song to the next level or say back to the drawing board....I will listen to crits and advice and I hope others do the same. It is the end product that counts.

http://www.soundclick.com/bands/songInfo.cfm?bandID=687727&songID=5238055